Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balances (in shares) at Dec. 31, 2017	1,221,064	138,492
Balances at Dec. 31, 2017	$ 1		$ 41,259	$ (79,982)	$ (38,722)
Issuance of common stock upon conversion of convertible promissory notes, related parties (in shares)		1,571,702
Issuance of common stock upon conversion of convertible promissory notes, related parties		$ 157	35,420		35,577
Issuance of common stock upon conversion of convertible preferred stock (in shares)	(1,221,064)	1,918,543
Issuance of common stock upon conversion of convertible preferred stock	$ (1)	$ 192	(191)
Reclassification of warrant to equity			70		70
Issuance of common stock upon reverse merger (in shares)		3,510,439
Issuance of common stock upon reverse merger		$ 365	31,403		31,768
Issuance of common stock upon exercise of stock options (in shares)		2,013
Issuance of common stock upon exercise of stock options			13		13
Stock-based compensation			86		86
Net income (loss)				2,314	2,314
Issuance of common stock warrants			70		70
Balances (in shares) at Mar. 31, 2018		7,141,189
Balances at Mar. 31, 2018		$ 714	108,060	(77,668)	31,106
Balances (in shares) at Dec. 31, 2017	1,221,064	138,492
Balances at Dec. 31, 2017	$ 1		41,259	(79,982)	(38,722)
Net income (loss)					(6,557)
Balances (in shares) at Jun. 30, 2018		7,141,189
Balances at Jun. 30, 2018		$ 714	108,178	(86,539)	22,353
Balances (in shares) at Mar. 31, 2018		7,141,189
Balances at Mar. 31, 2018		$ 714	108,060	(77,668)	31,106
Stock-based compensation			118		118
Net income (loss)				(8,871)	(8,871)
Balances (in shares) at Jun. 30, 2018		7,141,189
Balances at Jun. 30, 2018		$ 714	108,178	(86,539)	22,353
Balances (in shares) at Dec. 31, 2018		7,141,189
Balances at Dec. 31, 2018		$ 714	108,513	(97,989)	11,238
Reclassification of warrant to equity			100		100
Stock-based compensation			164		164
Net income (loss)				(1,339)	(1,339)
Cumulative effect of adoption of new leases standard at Dec. 31, 2018				(27)	(27)
Balances as of January 1, 2019, as adjusted at Dec. 31, 2018		$ 714	108,513	(98,016)	11,211
Issuance of common stock and warrants, net of offering costs (in shares)		1,200,000
Issuance of common stock and warrants, net of offering costs		$ 120	2,320		2,440
Issuance of common stock warrants			100		100
Balances (in shares) at Mar. 31, 2019		8,341,189
Balances at Mar. 31, 2019		$ 834	111,097	(99,355)	12,576
Balances (in shares) at Dec. 31, 2018		7,141,189
Balances at Dec. 31, 2018		$ 714	108,513	(97,989)	11,238
Net income (loss)					(6,976)
Cumulative effect of adoption of new leases standard at Dec. 31, 2018				(27)	(27)
Balances as of January 1, 2019, as adjusted at Dec. 31, 2018		$ 714	108,513	(98,016)	11,211
Balances (in shares) at Jun. 30, 2019		15,785,735
Balances at Jun. 30, 2019		$ 1,579	119,258	(104,992)	15,845
Balances (in shares) at Mar. 31, 2019		8,341,189
Balances at Mar. 31, 2019		$ 834	111,097	(99,355)	12,576
Reclassification of warrant to equity			333		333
Stock-based compensation			180		180
Net income (loss)				(5,637)	(5,637)
Issuance of common stock and warrants, net of offering costs (in shares)		925,455
Issuance of common stock and warrants, net of offering costs		$ 93	7,648		7,741
Issuance of common stock warrants			333		333
Issuance of common stock upon exercise of pre-funded warrants (in shares)		6,519,091
Issuance of common stock upon exercise of pre-funded warrants		$ 652			652
Balances (in shares) at Jun. 30, 2019		15,785,735
Balances at Jun. 30, 2019		$ 1,579	$ 119,258	$ (104,992)	$ 15,845